The present invention relates generally to wheelchairs, and more particularly, to a wheelchair having a support structure which provides improved freedom of movement to its occupant.
Various devices are known in the art for assisting, manipulating, transferring and transporting the disabled, and in particular paraplegics. Among the problems experienced by disabled individuals in daily living is the need to transfer from a wheelchair to devices which are higher than the wheelchair, and the need to reach things above the height of their wheelchair or beyond the reach of their outstretched arms. As well, individuals experience other problems related to prolonged sitting in chairs, such as the pooling of blood in lower extremities which causes dizziness.
These problems present obstacles at home and limit employment opportunities. The risk of falling is always present during transfer between a wheelchair and other devices, as is the risk of tipping when reaching upward or outward. The concomitant need for assistance results in higher insurance, medical and living costs, and sometimes causes loss of self-esteem and guilt in disabled individuals.
Numerous clinical devices have been developed to assist in the transfer of patients and disabled individuals. For example, Koenigkramer et al, U.S. Pat. No. 2,512,160, issued Jun. 20, 1950, disclose a patient carriage having a table mounted on balls in a support frame. The balls permit the table to be freely moved side-to-side, forward and backward, and rotated in a limited arc. The table is also capable of being raised vertically by a hydraulic cylinder, and its support frame is mounted on casters. More recently, Ooka et al, U.S. Pat. No. 4,794,655, issued Jan. 3, 1989 and Plewright et al, U.S. Pat. No. 4,839,933, issued Jun. 20, 1989 disclose patient transfer devices having movable table surfaces for transferring patients to adjacent surfaces, as well as means for adjusting those surfaces to place the patient in a supine or reclined position or a sitting position. These patents, as well as Furniss, U.S. Pat. No. 4,760,615, issued Aug. 2, 1988 include means for elevating the table surface. Other patient manipulation devices have been developed in which belts are used to secure an invalid or patient for movement, for example, Weiner, U.S. Pat. No. 4,761,842, issued Aug. 9, 1988.
The drawback of many of these transfer and transport devices is that, as clinical devices, many are not adaptable for home use, often requiring an assistant for operation rather than being user-operable. Some involve prolonged set-up time. Further, many individuals do not like being strapped in devices, where multiple straps are used to retain and secure the occupant.
Other devices for transferring and transporting the disabled from different levels have been developed which are more amenable to use in a home environment. For example, Kuhlman, U.S. Pat. No. 4,606,082, issued Aug. 19, 1986, discloses a chair lift apparatus for lifting and transporting individuals from wheelchairs into a bath or shower. Individuals may transfer from a specially designed wheelchair, whose back may be folded down, into the chair of the chair lift. The chair of the chair lift is suspended from a ceiling-mounted track, and is operable much like a crane by the occupant. The device of this patent, however, is confined in operation to a given path in which tracks are mounted in the ceiling, and thus is both expensive to install and inflexible in its range of use. Further, it is necessary to use a special wheelchair in connection with the chair lift.
Anderson et al, U.S. Pat. No. 3,936,893, issued Feb. 10, 1976, discloses a wheelchair which raises from a normal level to bed level while converting from a chair to a bed. The wheelchair of this patent has the drawback that an assistant is required to convert the device between the chair and bed configurations.
Accordingly, the need continues to exist for devices which provide enhanced mobility and freedom for disabled individuals, and which are operable by the individual, to improve independent living capabilities and employment opportunities, as well as to enhance self-esteem.